/**
 * NostrConnectModal — UI for connecting a Nostr identity on mobile.
 *
 * Android: offers "Connect with Amber" (NIP-55) as the primary action,
 *   with manual nsec entry as a secondary option.
 * iOS / other: manual nsec entry only.
 */

import React, { useCallback, useState } from "react";
import {
  ActivityIndicator,
  Modal,
  Platform,
  Pressable,
  StyleSheet,
  Text,
  TextInput,
  View,
} from "react-native";
import { Ionicons } from "@expo/vector-icons";

import { Colors } from "@/constants/colors";
import { useNostr } from "@/context/NostrContext";

// ─── Props ────────────────────────────────────────────────────────────────────

type Props = {
  visible: boolean;
  onClose: () => void;
};

// ─── Component ────────────────────────────────────────────────────────────────

export function NostrConnectModal({ visible, onClose }: Props) {
  const C = Colors.dark;
  const { connectWithAmber, connectWithNsec, canUseAmber } = useNostr();

  const [showNsecForm, setShowNsecForm] = useState(!canUseAmber);
  const [nsecInput, setNsecInput] = useState("");
  const [error, setError] = useState<string | null>(null);
  const [loading, setLoading] = useState(false);

  const handleClose = useCallback(() => {
    setNsecInput("");
    setError(null);
    setShowNsecForm(!canUseAmber);
    onClose();
  }, [canUseAmber, onClose]);

  const handleAmberPress = useCallback(async () => {
    setError(null);
    setLoading(true);
    try {
      await connectWithAmber();
      // Amber opens; the result arrives via deep-link callback.
      // Close the modal — NostrContext handles the incoming URL.
      handleClose();
    } finally {
      setLoading(false);
    }
  }, [connectWithAmber, handleClose]);

  const handleNsecConnect = useCallback(async () => {
    if (!nsecInput.trim()) {
      setError("Please enter your nsec key");
      return;
    }
    setError(null);
    setLoading(true);
    const result = await connectWithNsec(nsecInput.trim());
    setLoading(false);
    if (result.success) {
      handleClose();
    } else {
      setError(result.error);
    }
  }, [nsecInput, connectWithNsec, handleClose]);

  return (
    <Modal
      visible={visible}
      animationType="slide"
      transparent
      onRequestClose={handleClose}
    >
      <View style={styles.overlay}>
        <View style={[styles.sheet, { backgroundColor: C.surface, borderColor: C.border }]}>
          {/* Header */}
          <View style={styles.header}>
            <Text style={[styles.title, { color: C.text }]}>Connect Nostr Identity</Text>
            <Pressable onPress={handleClose} hitSlop={12}>
              <Ionicons name="close" size={22} color={C.textSecondary} />
            </Pressable>
          </View>

          {/* Android: Amber option */}
          {canUseAmber && !showNsecForm && (
            <View style={styles.body}>
              <Text style={[styles.description, { color: C.textSecondary }]}>
                Connect using{" "}
                <Text style={{ color: C.text, fontWeight: "600" }}>Amber</Text>{" "}
                — your keys stay in Amber and are never exposed to this app.
              </Text>

              <Pressable
                onPress={handleAmberPress}
                disabled={loading}
                style={({ pressed }) => [
                  styles.primaryButton,
                  { backgroundColor: C.accent, opacity: pressed || loading ? 0.75 : 1 },
                ]}
              >
                {loading ? (
                  <ActivityIndicator color={C.textInverted} />
                ) : (
                  <>
                    <Ionicons name="shield-checkmark" size={18} color={C.textInverted} />
                    <Text style={[styles.buttonText, { color: C.textInverted }]}>
                      Connect with Amber
                    </Text>
                  </>
                )}
              </Pressable>

              <Pressable
                onPress={() => setShowNsecForm(true)}
                style={styles.secondaryLink}
              >
                <Text style={[styles.secondaryLinkText, { color: C.link }]}>
                  Enter nsec manually instead
                </Text>
              </Pressable>
            </View>
          )}

          {/* nsec form */}
          {showNsecForm && (
            <View style={styles.body}>
              {canUseAmber && (
                <Pressable
                  onPress={() => { setShowNsecForm(false); setError(null); }}
                  style={styles.backLink}
                >
                  <Ionicons name="arrow-back" size={14} color={C.link} />
                  <Text style={[styles.secondaryLinkText, { color: C.link }]}>
                    Use Amber instead
                  </Text>
                </Pressable>
              )}

              <Text style={[styles.description, { color: C.textSecondary }]}>
                Paste your{" "}
                <Text style={{ color: C.text, fontWeight: "600" }}>nsec1…</Text>{" "}
                private key. It will be stored only in the device secure keystore
                and never logged or transmitted.
              </Text>

              <TextInput
                style={[
                  styles.input,
                  {
                    backgroundColor: C.field,
                    color: C.text,
                    borderColor: error ? C.destructive : C.border,
                  },
                ]}
                placeholder="nsec1…"
                placeholderTextColor={C.textMuted}
                value={nsecInput}
                onChangeText={(t) => { setNsecInput(t); setError(null); }}
                autoCapitalize="none"
                autoCorrect={false}
                secureTextEntry
                editable={!loading}
              />

              {error && (
                <Text style={[styles.errorText, { color: C.destructive }]}>
                  {error}
                </Text>
              )}

              <Pressable
                onPress={handleNsecConnect}
                disabled={loading}
                style={({ pressed }) => [
                  styles.primaryButton,
                  { backgroundColor: C.accent, opacity: pressed || loading ? 0.75 : 1 },
                ]}
              >
                {loading ? (
                  <ActivityIndicator color={C.textInverted} />
                ) : (
                  <Text style={[styles.buttonText, { color: C.textInverted }]}>
                    Connect
                  </Text>
                )}
              </Pressable>
            </View>
          )}
        </View>
      </View>
    </Modal>
  );
}

// ─── Styles ───────────────────────────────────────────────────────────────────

const styles = StyleSheet.create({
  overlay: {
    flex: 1,
    justifyContent: "flex-end",
    backgroundColor: "rgba(0,0,0,0.6)",
  },
  sheet: {
    borderTopLeftRadius: 20,
    borderTopRightRadius: 20,
    borderWidth: 1,
    borderBottomWidth: 0,
    paddingHorizontal: 24,
    paddingTop: 20,
    paddingBottom: Platform.OS === "ios" ? 40 : 24,
  },
  header: {
    flexDirection: "row",
    justifyContent: "space-between",
    alignItems: "center",
    marginBottom: 16,
  },
  title: {
    fontSize: 18,
    fontWeight: "700",
  },
  body: {
    gap: 14,
  },
  description: {
    fontSize: 14,
    lineHeight: 20,
  },
  primaryButton: {
    flexDirection: "row",
    alignItems: "center",
    justifyContent: "center",
    gap: 8,
    paddingVertical: 14,
    borderRadius: 10,
  },
  buttonText: {
    fontSize: 16,
    fontWeight: "600",
  },
  secondaryLink: {
    alignItems: "center",
    paddingVertical: 4,
  },
  secondaryLinkText: {
    fontSize: 14,
  },
  backLink: {
    flexDirection: "row",
    alignItems: "center",
    gap: 4,
  },
  input: {
    borderWidth: 1,
    borderRadius: 10,
    paddingHorizontal: 14,
    paddingVertical: 12,
    fontSize: 14,
    fontFamily: Platform.OS === "ios" ? "Courier" : "monospace",
  },
  errorText: {
    fontSize: 13,
  },
});